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This fact sheet answers the most frequently
asked health questions about sulfur mustard blister agents
H/HD and HT. For more information,
you may call the ATSDR Information Center at 1-888-422-8737. This fact sheet is one in a series of summaries about hazardous substances and their health effects. It is important you understand this information because this substance may harm you. The effects of exposure to any hazardous substance depend on the dose, the duration, how you are exposed, personal traits and habits, and whether other chemicals are present.

Highlights

Exposure to sulfur mustard agents H/HD and HT can occur due to accidental release from a military storage facility. Exposure to sulfur mustards can burn the skin and eyes, cause blisters, and cause respiratory effects such as coughing and bronchitis. Higher levels may cause death. Sulfur mustard agent H/HD has been identified at 3 of the 1,585 National Priorities List sites identified by the Environmental Protection Agency (EPA).

What are sulfur mustard agents H/HD and HT?

Sulfur mustards H/HD and HT are manufactured
compounds. They are colorless when pure, but are typically
yellow to brown oily liquids with a slight garlic or mustard
odor. Agent H contains about 20-30% impurities. The nearly
pure substance is called HD. HT is a mixture of 60% HD and
40% of another substance called agent T. They do not dissolve
much in water, but dissolve easily in oils, fats, and other
solvents. They are stable at ambient temperatures.

Sulfur mustards were introduced as chemical
warfare agents during World War I. More than a dozen countries
have sulfur mustard agents in their chemical arsenals. Destruction
of U.S. stockpiles of chemical agents, including sulfur mustards,
was mandated by the Chemical Weapons Convention to take place
before April 2007.

How might I be exposed to sulfur mustard agents H/HD and HT?

The primary routes of potential human exposure to sulfur
mustards are inhalation and dermal contact. Sulfur mustards
are chemical warfare agents that can cause skin burns and
blisters and damage to the respiratory airways. Sulfur mustards
burn your skin and cause blisters within a few days of exposure.
Exposure is particularly harmful around sweaty parts of
the body. It is also more harmful to the skin on hot, humid
days, or in tropical climates. Sulfur mustards make your
eyes burn, your eyelids swell, and cause you to blink a
lot.

If you breath sulfur mustards, it can cause coughing,
bronchitis, and long-term respiratory disease. If you are
exposed to large amounts of sulfur mustards, you can eventually
die from it.

Sulfur mustards did not affect reproduction in rats that
breathed it. We do not know if sulfur mustards can affect
people's ability to reproduce.

How can sulfur mustard agents H/HD and HT affect my health?

The primary routes of potential human
exposure to sulfur mustards are inhalation and dermal contact.
Sulfur mustards are chemical warfare agents that can cause
skin burns and blisters and damage to the respiratory airways.
Sulfur mustards burn your skin and cause blisters within a
few days of exposure. Exposure is particularly harmful around
sweaty parts of the body. It is also more harmful to the skin
on hot, humid days, or in tropical climates. Sulfur mustards
make your eyes burn, your eyelids swell, and cause you to
blink a lot.

If you breath sulfur mustards, it can
cause coughing, bronchitis, and long-term respiratory disease.
If you are exposed to large amounts of sulfur mustards, you
can eventually die from it.

Sulfur mustards did not affect reproduction
in rats that breathed it. We do not know if sulfur mustards
can affect people's ability to reproduce.

How likely are sulfur mustard agents H/HD and HT to cause cancer?

The Department of Heath and Human Services
(DHHS) has determined that blister agent H/HD is a known human
carcinogen. The International Agency for Research on Cancer
(IARC) has classified agent H/HD as carcinogenic to humans.
Studies in humans indicate that long-term exposure to sulfur
mustards may lead to cancer of the upper respiratory airways.

How do sulfur mustard agents H/HD and HT affect children?

There are no studies of children exposed
to sulfur mustard agents H/HD or HT. Children exposed to sulfur
mustard agents H/HD or HT are likely to experience the same
toxic effects experienced by exposed adults. In general, children
may be more vulnerable to corrosive agents than adults because
of the smaller diameter of their airways.

Sulfur mustards did not cause birth defects
in rats that breathed it. We do not know if these substances
can cause birth defects or other developmental effects in
humans.

How can families reduce the risk of exposure to sulfur mustard agents H/HD and HT?

Is there a medical test to show whether I've been exposed to sulfur mustard agents H/HD and HT?

There is no effective medical test to determine if you have been exposed to sulfur mustards.
A breakdown product of sulfur mustards can be measured in urine, but this chemical can also be found in people who
have not been exposed to sulfur mustards.

Has the federal government made recommendations to
protect human health?

An Airborne Exposure Limit (as recommended by the Surgeon General's Working Group,
U.S. Department of Health and Human Services) of 0.003 milligrams of H/HD or HT per cubic meter of air (0.003 mg/m³)
has been established as a time-weighted average (TWA) for the workplace.

ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in
recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.

Information line and technical assistance:
Phone: 888-422-8737

To order toxicological profiles, contact:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Phone: 800-553-6847 or 703-605-6000

Disclaimer
Some PDF files may be electronic conversions from paper copy or other electronic ASCII text files. This conversion may have resulted in character translation or format errors. Users are referred to the original paper copy of the toxicological profile for the official text, figures, and tables. Original paper copies can be obtained via the directions on the toxicological profile home page, which also contains other important information about the profiles.

The information contained here was correct at the time of publication. Please check with the appropriate agency for any changes to the regulations or guidelines cited.